Maryland Geological Survey 423 



correlatiox with xew york 



The Upper Devonian of this country was first studied with care in the 

 state of New Yorlc, from wliicli area many of the formational names were 

 derived. Continued investigation lias rendered our knowledge of the 

 Devonian of that state more accurate and detailed than that of any other 

 region in America. The correlation of the Jennings "with the Upper 

 Devonian of New York will therefore be considered first and after this 

 its relation to corresponding strata in Pennsylvania. The correlation 

 with the Upper Devonian of West Virginia is considered in the discussion 

 of the local sections. 



The Jennings formation is intimately related to the marine Upper De- 

 vonian of New York. This will be seen best by considering the congela- 

 tion of the various members of the Jennings with the corresponding 

 strata of New York. 



Genesee Shale Member. — A list of species that occur in the Genesee 

 shale menilter has been given on a preceding page. Among the most 

 abundant foi-ms are: Buchiola retrostriata, Ptcrodicenia fragilis, Styli- 

 olina fissurella, and various goniatites. Two of the species are new. All 

 of the remainder are found in the Genesee of New York in which 

 Sfulinliiiii. fissiiri'lln, PtcrocJia'ma fragilis and species of BucliioJa are 

 abundant. 



The strata of this member are similar lithologically to those of the 

 Genesee of New York, both being black, carbonaceous shales, while they 

 occupy a like stratigraphic position. Both also attain their maximum 

 thickness in the west and become thinner and disappear eastwards. 



The close resemblance of these strata in fauna, lithology, stratigraphic 

 position, and geographic distribution, fully justifies their correlation 

 with the Genesee formation of New York as has been published by Prosser. 



WooDMONT Shale Member. — The Woodmont shale member has been 

 shown to consist of two divisions. The lower of these contains the Naples 

 fauna and is equivalent to the Sherburne of New York. The upper con- 

 tains the Ithaca fauna and is equivalent to the Ithaca of that state. 



